Array antenna power supply system having power supply lines secured in a cylinder by adhesive

ABSTRACT

A power supply system adapted for an array antenna to be mounted on satellites, airplanes, ships, land moving objects, or the like, which is so arranged that a cylindrical member (136) is provided at a peripheral edge part of an opening (135) formed on a wall member (134) on which the antenna is to be mounted, a group of power supply lines (143) connected to a group of power supply connectors (124) are disposed in an interior of the cylindrical member (136), and the space between the interior of the cylindrical member (136) and the group of power supply lines (143) is sealed by an adhesive (146), thereby securing the air-tightness and water-tightness.

TECHNICAL FIELD

The present invention relates to an array antenna which is mounted onthe outside surface of an airplane body and so on, and also to a powersupply system for the antenna.

BACKGROUND ART

Heretofore, aircraft, whether military or civilian, have been equippedwith various sorts of communication or radar array antennas.

In an array antenna of the type referred to, a plurality of antennaelements are mounted on a base in a side-by-side positional relationshipand the antenna is usually mounted on the outside surface of an airplanebody (wall body).

Further, an array antenna installed on the outside, for which a highenvironmental resistance performance is demanded, employs in many casesa structure wherein the aforementioned antenna elements are enclosed bya radome.

FIG. 8 exemplifies a microstrip array antenna as described, whichcomprises a metallic base 1, a grounding plate 2, a dielectric substrate3, a radiation conductor 4 (antenna element), a coaxial cable 10 (powersupply means) which is fixed in the metallic base 1 and the groundingplate 2 as passed therethrough to supply power from the cable via acentral conductor 10a to the radiation conductor 4, these members beingsequentially stacked on the metallic base 1 in this order.

Fixed on the metallic base 1 by means of rivets 8 at its peripheral edgeis a radome 6 so that a metallic spacer 7 disposed between the radomeand the radiation conductor 4 maintains a predetermined gap 5.

In the prior art array antenna, however, not only external partsincluding the metallic base 1, the radome 6 and so on but also internalconstituent parts are all formed in a planar configuration. For thisreason, in order for the prior art array antenna to be fixedly mountedon such a curved surface as the outside surface of an airplane, a spacer12 must be provided between the bottom surface of the metallic base 1and an airplane body 11 and as shown in FIG. 9.

Such provision of the spacer, however, causes an increase of aprojection h of the array antenna from the airplane body at its bothends, which results in that the air resistance of the antenna isincreased and thus this involves the vibration and deformation of theradome 6 due to the air pressure.

Since the radome 6 is usually made of such dielectric material as resin,a deformation in the radome 6 positioned in a beam radiation path causesa variation in the total dielectric constant of the radiation conductor4 above it, which affects the beam characteristics of the antenna.

Further, the repetitive deformation of the radome 6 has a great effecton the mechanical strength of the radome 6 itself.

Meanwhile, this sort of array antenna to be externally installedincludes a connector which passes through the airplane body to connectthe respective antenna elements and a transmitter/receiver.

This is realized in the prior art, by positioning a flange part 24 of aconnector 23 on an outer surface of an airplane body 25 and tighteningthe flange part 24 to the airplane body 25 through a packing 26 tothereby maintain the interior of the airplane body 25 in an air-tightcondition, as shown in FIG. 10.

In the event where it is necessary to supply power individually to amultiplicity of antenna elements as in a phased array antenna, however,the above technique requires the formation of a multiplicity of holes ina relative small zone on the airplane body 25, thus making it difficultto secure the strength of this zone and the air tightness of theairplane body and further involving a large number of hole formationsteps.

And this technique, when it is desired to make such holes in the body ofan existing airplane being used, involves more difficulties in attainingthat purpose.

In view of the above circumstances, it is an object of the presentinvention to provide an array antenna which can maintain the strength ofa casing on which the antenna is to be installed and also maintain theair-tightness of the casing.

DISCLOSURE OF INVENTION

In accordance with one aspect of the present invention, the above objectis attained by providing an array antenna wherein a plurality of antennaelements are arranged on a common base and the base and a radome forcovering the plurality of antenna elements are both formed to be curvedin accordance with the curved configuration of a wall body on which theantenna is to be mounted. Therefore, the total projection height of theantenna from the wall member can be minimized and made uniform.

In accordance with another aspect of the present invention, there isprovided a power supply system which comprises an opening provided in awall body on which an array antenna is to be mounted, a cylindricalmember provided at a peripheral edge part of the opening, a group ofpower supply connectors disposed at a location of the array antennacorresponding to the opening of the wall body, a group of power supplylines disposed in an interior of the cylindrical member to be connectedto the group of power supply connectors, and adhesive sealingly filledin the interior of the cylindrical member between the power supply linesto seal the cylindrical member.

With this power supply system, power supply can be realized in such acondition that the interior of a wall body on which the array antenna ismounted can be kept air-tight and water-tight.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front cross-sectional view showing an embodiment of amicrostrip array antenna in accordance with the present invention;

FIG. 2 is a plan view of the antenna of FIG. 1;

FIGS. 3 and 4 are cross-sectional views showing other embodiments of thearray antenna of the present invention, respectively;

FIG. 5 is a cross-sectional view showing an embodiment of a power supplysystem in accordance with the present invention;

FIG. 6 is a cross-sectional view showing an example in which the samepower supply system is applied to an array antenna;

FIG. 7 is a fragmentary plan view of the antenna of FIG. 6;

FIG. 8 is a cross-sectional view showing a prior art array antenna;

FIG. 9 is a conceptional diagram showing a state in which the prior artarray antenna is fixedly mounted on the body of an airplane; and

FIG. 10 is a fragmentary cross-sectional view showing a prior art powersupply system.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIGS. 1 and 2, there is shown an embodiment of an arrayantenna in accordance with the present invention, respectively in across sectional view and in a plan view. The antenna of the presentembodiment is of an array type in which a plurality of microstripantenna elements are arranged and which functions, when the phase ofthese antenna elements is controlled, as a so-called sequencial arrayantenna.

As best seen in FIG. 1, the microstrip antenna comprises a base 31, agrounding plate 32, a dielectric substrate 33, a plurality of conductors34 positioned as spaced at intervals of a predetermined distance on thedielectric substrate 33, coaxial cables 40 which are fixed as passedthrough the base 31 and the grounding plate 32 and central conductors40a of which are connected to the respective radiation conductors 34, apaper honeycomb material 45 filled in a space defined between thedielectric substrate 33 and a radome 36, these members beingsequentially stacked on the base 31 in this order.

The base 31, the grounding plate 32, the dielectric substrate 33 and theradome 36 are formed to be respectively curved so as to coincide withthe curved configurations of an outside surface of an airplane body 47.For this reason, the bottom surface (base 31) of the antenna can bebrought into a tight contact with the outside surface of the airplanebody 47 and the curvature of the outside surface of the radome 36 can bemade equal to that of the outside surface of the airplane body 47.

The respective radiation conductors 34 may be formed to be curved so asto coincide with the curvature of the airplane body 47 or may be formedto be planar.

The coaxial cables 40 corresponding in number to the radiationconductors 34 have been led out from the interior of the airplane bodyin the foregoing embodiment. However, when a distributor/compositer isprovided for supplying power to the respective radiation conductors 34,it is suffice to use a single coaxial cable as a power supply line. Atechnique using such a distributor/compositer can be commonly appliedeven in other embodiments which will be explained in the following.

Mounting of the radome 36 can be carried out by covering the radome 36on the paper honeycomb material 45 under such a condition that the paperhoneycomb material 45 is placed on the dielectric substrate 33, and thenby fixing the peripheral edge portion of the base 31 and radome 36 bymeans of rivets 38.

Since the paper honeycomb material 45 functions to support the radome 36as contacted with the inner wall surface thereof, the supportingstrength of the antenna can be improved to a large extent, thevibrational resistance can be improved, and further the influencesexerted by wind pressure or pressure difference can be reduced to alarge extent.

The honeycomb material 45, which is made of paper, has a dielectricconstant of about 1 (corresponding to air). Thus, even when thehoneycomb is disposed as tightly contacted with the radiation conductor34, this will cause no disturbance of excitation mode of a beam radiatedfrom the radiation conductors and therefore will cause no variation inthe characteristics of the microstrip antenna. In addition, because ofthe honeycomb 45 made of paper, the antenna can be greatly reduced inweight so that the weight limitations imposed on prior art antennas forairplane mounting can be easily cleared, whereby the antenna of thepresent invention using the paper honeycomb can expand its structuraldesign flexibility when compared with the prior art antenna using ametallic spacer.

Shown in FIG. 3 is a microstrip array antenna in accordance with anotherembodiment of the present invention, which antenna includes a base 51which forms the bottom plate of the antenna, a first grounding layer 52made of dielectric material, a first dielectric substrate 70, LCmatching circuits 71 of strip lines for impedance matching, a seconddielectric substrate 74, a second grounding layer 76, a third groundinglayer 78, a third dielectric substrate 80, a radome 56 disposed to coverthese members, these members being sequentially stacked on the base 51in this order.

The radome 56 is fixedly mounted on the base 51 by means of rivets 55.The radome 56 is provided in its inner bottom surface with a pluralityof recessed 56a which are spaced from each other at intervals of apredetermined distance, and radiation conductors 54 are embedded in therespective recesses 56a.

The base 51 and the members sequentially stacked on the base 51 areformed to be curved so that theses members have the same curvature asthe curved surface of a airplane body 47.

Coaxial cables 60 are fixed as passed through the base 51 and the firstgrounding layer 52 and have central conductors 60a connected to theassociated LC matching circuits respectively. The LC matching circuits71 are connected to the associated radiation conductors 54 by means ofassociated power supply pins 85.

The first and second grounding layers 52 and 76 enclose or sandwich theLC matching circuits 71 from upper and lower sides thereof and the thirdgrounding layer 78 is disposed as opposed to the radiation conductors54. The grounding layers 76 and 78 may be replaced by a single groundinglayer which has the same functions as the layers 76 and 78.

The radiation conductors 54 have lower sides contacted with the upperside of the dielectric substrate 80 and also receive power from therespective power supply pins 85.

When the radome 56 is tightly contacted with the radiation conductors54, this causes change of the excitation mode above the radiationconductors, whereby the antenna characteristics, in particular, theimpedance characteristic is varied to a greater extent compared with thesituation where the radome 56 is not used. In the present embodiment,such an impedance variation problem is solved by providing the matchingcircuits 71 in the input terminal portions to match the input impedanceat a desired value. With such an arrangement, a variation in the inputimpedance characteristics caused by the close contact of the radome withthe radiation conductors can be compensated for.

As has been explained above, in accordance with the embodiments shown inFIGS. 1 and 3, since the overall configuration of the array antennaincluding the radome is curved so as to coincide with the surfaceconfiguration of the airplane body 47 or the like, the total projectionheight of the antenna can be minimized.

Accordingly, it is possible to solve various problems in the prior artwhich have so far easily occurred when mounted on an airplane. Morespecifically, when the present invention is mounted on an airplane,since the air resistance can be reduced to a large extent, vibrations,expansions, shrinkages or other deformations in the radome caused bywind pressure can be prevented. As a result, the present invention canprevent the influences on the beam characteristics caused bydeformations in the radome positioned in the beam radiation path, theinfluences on the mechanical strength and further the deterioration ofan operating fuel cost.

Referring to FIG. 4, there is shown a further embodiment of themicrostrip array antenna in accordance with the present invention, whichantenna includes a base 91 which is installed on the surface of aairplane body 47 and which is also used as a grounding plate, a radome96 disposed on the base 91 to define a predetermined air gap 95 with theupper surface of the base 91, a plurality of radiation conductors 94disposed on the inner side of the radome 96 with the lower sides of theconductors being exposed to the air gap 95, and a group of coaxialcables 100 fixed as passed through the base 91 and having centralconductors 100a connected to the associated radiation conductors 94.

The base 91 is formed as curved so as to have the same curvature as thecurved surface of the airplane body 47, and the upper side of the radome96 is also formed as curved so as to have the same curvature as thecurved surface of the airplane body 47.

The air trapped in the gap 95 defined by the base 91 and the radiationconductors 94 functions as a dielectric material.

Even the present embodiment, like the foregoing embodiments, can preventthe deformation of the radome due to wind pressure. The presentembodiment is advantageous in that the number of necessary parts can bereduced to simplify the structure, the height of the radome can be setto be sufficiently small and further the weight can be made small.

Although any one of the antennas shown in the foregoing embodiments hasbeen mounted on the surface of the airplane body 47, the antennas of theforegoing embodiments may be applied even to the curved wall or the likeof a moving object or a building other than the airplane. To this end,objects on which the antenna is to be mounted are expressed inclusivelyas "wall body" in claims. claims.

Explanation will next be made as to an embodiment of a power supplysystem in accordance with the present invention.

Prior to the explanation of the embodiment, the general arrangement ofan array antenna to which the present embodiment is applied, inparticular, of an array antenna having a flat radiation surface forelectromagnetic waves, will first be briefly explained.

FIGS. 6 and 7 are fragmentary cross-sectional and rear views of amicrostrip phased array antenna of a rear two-point power supply typehaving flat radiation patches. Each one of antenna elements of theantenna includes a radiation patch 116 of, for example, a circular shapedisposed on the front side of a dielectric material 115 (see FIG. 6)which forms a predetermined capacitance, a grounding plate 117 providedon the rear side of the dielectric material 115, a printed circuit board119 bonded with adhesive on the rear side of the grounding plate 117 onwhich a hybrid circuit 118 is formed as shown in FIG. 7, and pins 120and 121 passed through the dielectric material 115 and the printedcircuit board 119 to connect the radiation patch 116 and the hybridcircuit 118.

With such an antenna element, power is supplied to the radiation patch116 through the pins 120 and 121. In this case, when a phase differencebetween high frequency currents at power supply points 122 and 12 (seeFIG. 7) is set to be a predetermined angle, and generally to be 90degrees and further when the impedances at the power supply points 122and 123 are matched at, for example, 50 ohms; the antenna element canradiate or receive circularly polarized electromagnetic waves. And whena multiplicity of such antenna elements are arranged and the phase ofpower supplied to the respective elements is sequentially rotated, aphased array antenna can be configured.

The hybrid circuit 118 is connected at its one end with a connector 124fixedly mounted on the printed circuit board 119 and power supply to theantenna element is carried out through the connector 124.

The other end of the circuit 118 is soldered to the grounding plate 117at a point 126 through a proper resistor 125.

The grounding side of the connector 124 is also soldered to thegrounding plate 117 at a point 127 (see FIG. 7).

Further, the grounding plate 117 must be electrically connected to,e.g., the surface of an airplane body. However, the hybrid circuit 118is provided on the rear side of the grounding plate 117 and may cause ashort-circuiting. In FIG. 6 for the purpose of avoiding such ashort-circuiting, a suitable insulating plate 128 is provided to abut atits peripheral part against the grounding plate 117 and the groundingplate 117 is grounded to the airplane body through an electricallyconductive sheet 129 attached onto the rear side of the insulating plate128. In this connection, interconnection between the grounding plate andthe conductive sheet 129 is effected by joining with solder thegrounding plate 117 to the protective insulating plate 128 at a suitablepoint 130 in its end part or opening.

The array antenna comprising a multiplicity of such antenna elementsarranged as mentioned above can be made basically in the form of ahighly thin plate and thus can avoid the increase of the aerodynamicresistance, whereby the antenna can be suitably used as an antenna in acommunication system designed for mounting on an airplane.

FIG. 5 shows an embodiment of the power supply system 150 in accordancewith the present invention, which is applied to the aforementioned arrayantenna mounted on the pressurized bulkhead, airplane body or the likeof an airplane.

In the drawing, a multiplicity of radiation patches 116 are arranged ona board 131 in a planar form, and the board 131 abuts against apressurized bulkhead 134 in such a condition that the board 131 issandwiched in between a radome 132 and a shim 133 made of aluminumalloy.

The shim is formed to be tightly contacted with a grounding conductivesheet 129 provided on the board 131 and to be fitted to the curvedoutside surface of the pressurized bulkhead 134.

Meanwhile, the pressurized bulkhead 134 is provided therein with anopening 135 which can accommodate therein a group of connectors 124projected from the board 131 so as to avoid the grounding conductivesheet 129 attached onto the rear side of the board 131. A cylindricalmember 135 is fixed by screws 137 to the shim 133 at the peripheral partof an opening made in the shim 133 which is slightly smaller in innerdiameter than the opening 135 and which abuts against the opening 135 assubstantially concentric therewith, so that the cylindrical member 136passes through the opening 135 of the bulkhead 134 and depends from theboard 131 into the interior of the bulkhead 134.

The cylindrical member 136 is provided at its outer circumferencial partwith a threaded part 138 which is in threaded engagement with a nut 139.Since a packing 140 and a spring washer 141 are provided between the nut139 and the bulkhead 134, the air tightness of the opening 135 in thebulkhead can be secured and the mechanical fixation of the cylinder 136can be attained by tightening the nut 139.

The shim 133 is fixedly secured at its outer peripheral edge to thepressurized bulkhead 134 by tightly screwing bolts into the associatedinternal female threaded holes of air-tight pins 142 fixedly attached tothe bulkhead 134.

The connectors 124 are connected with associated power supply coaxialcables (power supply lines) 143, 143, . . . respectively. The cables 143are previously passed through an opening 144a provided in a lid 144 ofthe cylindrical member 136. And the connectors 124 are fixed to theboard 131 and thereafter the open end of the cylinder 136 is fixedlycovered with the lid 144.

After fixation of the lid 144, epoxy or silicon series adhesive 146 isfilled into the interior of the cylindrical member 136 from an inletport 145 provided in the lid 144 and then solidified or set therein.

With such a structure, even if the antenna radome 132 is destroyedthrough the collision of birds or the like against the radome and theair tightness of the opening 135 in the pressurized bulkhead 134 isdestroyed, this will not affect the interior of the pressurized cabin ofthe airplane.

The afore-mentioned power supply system has been applied to themicrostrip array antenna of the type wherein power is supplied from therear side of the antenna element to the radiation patch at the twopoints in the foregoing example, but the power supply system may also besupplied to an antenna wherein power supply to a radiation patch iseffected at one point and to an antenna wherein a power supply point orpoints are provided at the edge of a radiation patch.

Further, the power supply connectors 124 to the radiation patch havebeen provided concentrately at one location in the embodiment of FIG. 5.However, in the case where the number of such radiation patches islarge, the power supply connectors may be divided into two or moregroups and the connector groups may be separately concentratedlylocated. Even in such a case, the power supply system of the presentinvention can be effectively employed, as a matter of course.

Furthermore, the power supply system of the present invention is notrestricted as its applications only to the planar antenna but may beapplied to any sort of antenna so long as it is an array antenna whereinarray antenna elements are arranged.

In addition, the application objectives of the power supply system ofthe present invention are not limited only to airplanes but also mayinclude space navigation vehicles, warships, vessels, land movingobjects, which require air-tightness or water-tightness in the spaceinside the outboard thereof.

INDUSTRIAL APPLICABILITY

An array antenna in accordance with the present invention is highlyeffective as an antenna to be mounted on an airplane which requires themounted antenna to be low in its mounted height.

Further, since a power supply system in accordance with the presentinvention can supply power to an array antenna while keeping its airtightness and water tightness, the system can be effectively applied toan array antenna to be mounted, in particular, on the pressurizedbulkhead or the like of an airplane.

We claim:
 1. A power supply system for an array antenna including aplurality of antenna of antenna elements, a wall body having an outersurface and defining a wall opening over which said array antenna ismounted, comprising:a shim having a surface fitted over the outersurface of the wall body, the shim surface disposed in contact with theouter surface of said wall body, said shim defining a shim opening at aposition corresponding to said wall opening; a board member on whichsaid plurality of antenna elements are disposed, said board member beingdisposed on said shim; a hollow cylindrical member provided at aperipheral edge part of said shim opening and extending through the wallopening of said wall body; a plurality of power supply connectorsdisposed on the board member at the shim opening, each of said powersupply connectors being connected to a corresponding one of the antennaelements; a plurality of power supply lines disposed in an interior ofsaid cylindrical member, each power supplied line being connected to acorresponding one of said power supply connectors; and adhesive materialdisposed in the interior of said cylindrical member around said powersupply lines to an inner wall of said cylindrical member for preventingair from passing through the cylindrical member.
 2. A power supplysystem as set forth in claim (1), wherein said power supply connectorsare housed in the interior of said cylindrical member.